New Zealand·Calculators·Mortgage

Mortgage repayment calculator

Repayments use the standard amortisation formula: P x [r(1+r)^n] / [(1+r)^n - 1]. Enter the loan amount, rate and term to calculate.

Your numbers

Loan amount

$NZD

Interest rate

% p.a.

Loan term

years

Extra repayment

$NZD / fortnight

Fortnightly repayment:

$2,050

26 payments a year over 30 years

Total interest$848,973

Total repaid$1,598,973

Interest per dollar borrowed1.13

Rate5.89%

The interest rate remains constant for the full loan term. Principal and interest payments are made at the selected regular frequency. Interest is divided evenly across 52, 26 or 12 periods per year. No fees, extra repayments, redraws, offsets, payment holidays or balloon payment. The editable RBNZ benchmark is market context, not an individual lender offer. Payments, interest, balances and totals are estimates rounded separately for display. Calculations use unrounded payments and interest, so displayed payments may not sum to the total. This is not a lender cash-flow schedule. Amounts over 90 trillion are past what this calculates.

Principal against interest over 30 years46.9% principal · 53.1% interest

Principal$750,00046.9%Interest$848,97353.1%

Which term should you fix for?

Every row uses the 5.89% rate you entered, held the same for every term. This site publishes no separate market rate for each fixed term, so no best rate is shown. Repayments are monthly, and the interest and total repaid cover that fixed period only.

Repayment schedule by fixed term
Term	Monthly repayment	Interest over term	Total repaid
6 months	$4,444	$22,031	$26,662
1 year	$4,444	$43,924	$53,325
2 years	$4,444	$87,279	$106,649
3 years	$4,444	$130,031	$159,974
5 years	$4,444	$213,576	$266,624

Source: Reserve Bank of NZ published averages · Effective 2026-09-30 · Checked 2026-10-10Using Reserve Bank of NZ rates

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How it works

The calculator uses the standard amortising loan formula. Each repayment covers the interest accrued since the last one, and whatever is left over reduces the balance. Early on, most of the payment is interest. Later, most of it is principal.

Changing frequency recalculates the payment, not the loan term. Interest uses the annual rate divided by payments per year, so total interest varies slightly with frequency.

The formula

Nothing is hidden here. This is the calculation running behind the number above.

payment = P × r ÷ (1 − (1 + r)⁻ⁿ)

Pthe amount borrowed

rthe interest rate for one period — annual rate ÷ payments per year

ntotal number of payments — years × payments per year

A worked example

Borrow $750,000 at 5.89% over 30 years, repaid fortnightly. The period rate is 5.89% ÷ 26, and there are 780 payments.

Amount borrowed$750,000

Payments780

Each payment$2,049.96

Interest over the term$848,973

Common questions

Does repaying fortnightly actually save money?

Payments are recalculated over the same term. An accelerated schedule pays half the monthly amount every two weeks: 26 payments equal 13 monthly payments. That extra-payment schedule is not modelled.

What happens when my fixed term ends?

You refix at whatever rates are available then, or roll onto the floating rate. This calculator assumes one rate for the whole term, so treat long-term totals as a shape, not a promise.

Should I make extra repayments?

Every extra dollar comes straight off the principal, so it saves you every future interest charge on that dollar. Check whether your fixed loan limits extra repayments before you commit.

Why is the bank's number different from mine?

Banks round differently, may charge fees inside the repayment, and sometimes calculate interest daily rather than per period. Expect a difference of a few dollars, not a few hundred.